(Phys.org)—Abhyudai Singh, assistant professor of electrical and computer engineering at the University of Delaware, describes a new method to understand sources of "noise" in gene-expression that create variability in ...

(Phys.org)—New research findings published in the Proceedings of the National Academy of Sciences (PNAS) are consistent with a controversial theory that an extraterrestrial body – such as a comet – impacted the Earth ...

(Phys.org)—A US scientist has proposed that a new planetary boundary be used to analyze the effects of human activities on the planet. He warns that there are definite biophysical limits to growth in human population, economies ...

After a two-day games hack in which scientists and games developers came together to create video games from doctoral research, a bacterial shoot-em-up game, 'Dysbiosis', has emerged as the winner of the Wellcome Trust's ...

The spread of disease between species is a "one health" issue affecting both human health and wildlife conservation according to a new set of papers published today by scientists from the Royal Society and ZSL.

Earth's growing human population needs fresh water for drinking and food production. However, fresh water is also needed for the growth of biomass, which acts as a sink of carbon dioxide and thus could help mitigate climate ...

World population

The term world population commonly refers to the total number of living humans on Earth at a given time. As of 29 July 2009, the Earth's population is estimated by the United States Census Bureau to be 6.774 billion. The world population has been growing continuously since the end of the Black Death around 1400. There were also short term falls at other times due to plague, for example in the mid 17th century (see graph). The fastest rates of world population growth (above 1.8%) were seen briefly during the 1950s then for a longer period during the 1960s and 1970s (see graph). According to population projections, world population will continue to grow until around 2050. The 2008 rate of growth has almost halved since its peak of 2.2% per year, which was reached in 1963. World births have levelled off at about 134-million-per-year, since their peak at 163-million in the late 1990s, and are expected to remain constant. However, deaths are only around 57 million per year, and are expected to increase to 90 million by the year 2050. Since births outnumber deaths, the world's population is expected to reach about 9 billion by the year 2040.